I built a kit from Antique Electronics for a hi-fi crystal set AM tuner.
It was from a company called 'Peebles Originals' model number POCR-AM3.
(I'm not sure if this kit is still in their mosy recent catalog.)

It was fun to build. I also got the pine cabinet which I lined with tin
foil to minimize noise. With a long wire antenna it sounds quite good
having a clarity missing from most modern tuners. However, living in
Los Angeles with a very crowded AM band the poor selectivity is an issue. Also, the output is very low so you need a fair amount of gain to get to a decent line level.

You might want to check it out.

I have also noticed that there is a schematic for a "Tubeless HiFi
Tuner" in volume one of _Audio Anthology_.

- Paul
In rec.audio.tubes Jon Noring wrote:
william_b_noble wrote:

I guess that I must be in the minority - it seems to me that for
best AM fidelity (not selectivity, nor sensitivity), you would use a
crystal set with tuned RF stages, no IF, no heterodyne of any kind.
Use the tubes for RF amps if needed, and for audio amplification,
and use a tube diode for the detector.

Actually, this setup intrigues me for local reception, since it
appears to be a quite simple circuit. Are there any schematics of such
a circuit -- any commercially made radio of yesteryear using this
design approach?

Jon